Imaging glare can impede or reduce printed tag information recognition. For example, glare has interferred with barcode detection and recognition of barcodes used in retail applications wherein various image-based and video-based analytics are being developed. Automated systems for determining the spatial layout of products in a store via barcode recognition are currently being developed but depend on accurate barcode recognition. Barcode recognition is a problem mostly due to glare caused by lighting existing in the environment where barcodes are being used. This problem is further exacerbated when barcodes are covered by clear plastic coatings. The problem equally applies to the recognition of other patterns or numbers, e.g., such as QR codes and UPC codes that are used to identify product and inventory and also applies in non-retail applications wherein accurate printed tag information detection and recognition is necessary.
Glare refers to saturated regions in images typically caused by specular reflection from the surface of an object being imaged and can impede recognition of printed information. For example, when a glare region overlaps a barcode region, image processing cannot resolve the bars in most cases because the barcode may be completely white or wiped out in the images due to gray-level saturation. An ideal solution is to have an imaging system that does not generate images with glare regions in the first place; but due to the lighting variability in and across stores and the constraints in imaging systems, it is not feasible in practice. To make the matter worse, most price-tags are inserted in a plastic strip at the facing of the shelf, where the plastic has a high degree of specular reflection and is positioned at an angle that reflects light from ceiling facility illumination into the direction of the imaging system. This combination of lighting and imaging geometry and high specular refection tends to increase the prevalence of glare when imaging tags are located on shelf facing.
What is needed are systems and methods that can overcome printed tag information recognition problems caused by glare. The present inventors describe systems and methods to enhance tag information recognition rates by reducing the effect of glare on printed tags during imaging.